Gun mount and gunsight assembly



March 21, 1967 Filed March 1, 1965 IFIE l C. W.'LYKAM GUN MOUNT AND GUNSIGHT ASSEMBLY '7 Sheets-Sheet l INVENTOR I CLARENCE W. LYKAM ATTORNEY March 21, 1967 c. w. LYKAM GUN MOUNT AND GUNSIGHT ASSEMBLY 7 Sheets-Sheet 2 Filed March 1, 1965 INVENTOR CLARENCE W. LYKAM ATTORNEY C. W. LYKAM GUN MOUNT AND GUNSIGHT ASSEMBLY March 21, 1967 7 Sheets-Sheet 4 II JQ INVENTOR CLARENCE W. LYKAM BY MW fif/aw /b.

Nb O o ow m 2: III! fl lm Filed March 1, 1965 m m rl ATTORNEY C. W. LYKAM GUN MOUNT AND GUNSIGHT ASSEMBLY March 21, 1967 Filed March 1, 1965 7 Sheets-Sheet 5 INVENTOR CLARENCE W. LYKAM BY M, -52 4fl.wu &,.

ATTORNEY March 1967 c. w. LYKAM 3,309,962

GUN MOUNT AND GUNSIGHT ASSEMBLY Filed March 1, 1965 7 Sheets-Sheet s INVENTOR CLARENCE W. LYKAM ATTORNEY March 21, 1967 c. w. LYKAM GUN MOUNT AND GUNSIGHT ASSEMBLY 7 Sheets-Sheet '2 Filed March 1, 1965 INVENTOR CLARENCE W. LYKAM ATTORNEY 3,309,962 GUN MOUNT AND GUNSIGHT ASSEMBLY Clarence W. Lykanr, San Jose, Calif., assignor to FMC Corporation,.San Jose, Calif., a corporation of Delaware Filed Mar. 1, 1965, Ser. No. 435,947 15 Claims. (Cl. 89-41) This invention relates to ordnance and more particularly to a gun and gunsight assembly wherein the gun is pedestal mounted and the gunsight is of the periscopic type. The gun and gunsight assembly of the present invention is shown mounted on a military vehicle such as a tank, with the gunner stationed below the top deck of the tank, at the eyepiece of the periscopic sight. However, it is to be understood that the present invention is not limited to mounting the weapon on any particular emplacement, or on any particular vehicle; land, water, or amphibious. In the present invention, the periscopic sight optically follows the motion of the gun in both azimuth and elevation, while the tubes and eyepiece of the gunsight remain fixed relative to the gun mounting base, such as the tank illustrated in the drawings.

An object of the invention is to provide a gun and gun mount assembly mounted on a hollow pedestal for motion in azimuth and elevation, and a periscopic gunsight having a periscope tube coaxially mounted with said pedestal, and having optics mechanically connected between the gun mount and the gunsight optics, for causing the gunsight to follow the gun in azimuth and in elevation.

It is also an object of the present invention to provide a gun and gunsight assembly of the type described, which always provides an erect image of the tar-get, the image being unaffected by both training of the gun in azimuth, and by depression and elevation of the gun.

More specifically, it is an object of the present invention to provide an assembly of the type described, wherein the motion of the gun in both azimuth and elevation operates optico-mechanical means in the gunsight, so that the image of the target, as viewed by the gunner, remains erect and fixed, in the sense that the images does not rotate, as a result of either training of the gun in azimuth, elevating and depressing the gun, or a combination of these two gun motions.

Another object of the present invention is a provision of a gun and gunsight assembly of the type described, which readily lends itself to a gun mounting which can be raised and lowered relative to the gun base.

Thus, the gun and gunsight assembly of the present invention is particularly useful as a pedestal mounted weapon on com-bat vehicles, where the pedestal supports the gun above the roof of the combat vehicles, and wherein the pedestal and gun can be lowered to bring at least the breech of the gun inside the vehicle for loading.

The manner in which these and other objects of the invention may be obtained by those skilled in the art will be apparent from the following detailed description of the invention, and the accompanying drawings.

In the drawings:

FIGURE 1 is a fragmentary side elevation of a military vehicle embodying the gun and gunsight assembly of the invention with parts broken away. The gun is shown at zero train and elevation in this figure.

FIGURE 2 is a fragmentary plan on the assembly of the present invention with parts of the gun broken away.

FIGURE 3 is a view like that of FIGURE 1, except that the gun and gun mount have been lowered into the body of the vehicle or tank that carries the weapon.

FIGURE 4 is an enlarged vertical section through the gun and gunsight assembly of the present invention, showing the gun train and elevation mechanisms.

United States Patent FIGURE 5 is an enlarged fragmentary side elevation showing a portion of the gun elevating mechanism.

FIGURE 6 is a view of the gun elevation mechanism as viewed along lines 66 of FIGURE 5.

FIGURE 7 is a diagrammatic perspective showing the relation of the gun (shown in phantom) to the gun mount and the fixed periscopic sight.

FIGURE 8 is a fragmentary side elevation of the gun and gun mount, showing the elevation connection between the gun and the elevation mirror of the gunsight.

FIGURE 9 is a fragmentary exploded perspective showing the gun elevation mechanism of FIGURES 5 and 6.

FIGURE 10 is an exploded view of the upper portion of the periscopic gunsight.

FIGURE 11 is a schematic diagram showing the relationship of the optical elements of the gunsight. In this view, the movable optical elements of the gunsight are shown in the position of zero gun azimuth or train, and zero gun elevation.

FIGURE 11A is a diagram showing ray tracing through a dove prism, which type of prism has been selected as the tie-rotating prism in the illustrated embodiment of the invention.

FIGURE 12 is a diagrammatic plan of the optical system of the gunsight.

General description of the gun mount Referring to FIGURE 1, a gun G is shown mounted above the upper deck or roof 10 of a military vehicle V, such as a tank. The deck is apertured at 11 to receive the gun breech and a tubular pedestal 12, forming a part of the gun mount indicated generally at M. The gun mount can be lowered to bring the gun breech inside the tank (FIG. 3), by means of a carriage 13 which forms the lower part of the gun mount M, and screwjack mechanism 13a controlled by a foot pedal 13 b, which controls a motor unit 132 for the screwjack assembly. Details of the carriage raising and lowering mechanism are not critical to the present invention, and hence are not described. The gun mount is locked in the raised position by mechanism (not shown) operated by a handle 13 FIGS. 1 and 3.

As best seen in FIGURE 4, the gun mount M includes a trunnion assembly including two trunnions 14, mounted on the pedestal 12 for gun rotation in azimuth. The pedestal 12 supports a tubular sleeve 16, which mounts the trunnion assembly 14, and the sleeve 16 is rotatably mounted on the pedestal 12 on bearings to accommodate rotation of the gun in azimuth. The gun G is mounted on the trunnions 14 by means of pins 18, for accommodating gun motion in elevation. The gunner manually clevates and depresses the gun by means of an elevation crank 18a, FIGURES 1, 3 and 4.

The gun trunnion assembly 14 and the gun, are trained in azimuth by a sprocket mechanism indicated generally at 19 (FIG. 4), operated by a combined azimuth handle and trigger assembly 19a.

The gun elevation mechanism is indicated generally at 20, and as will be seen, the gun train mechanism 19, and the gun elevation mechanism 20, are constructed so that portions of these mechanisms within the vehicle neither train nor elevate with the gun, whereas the portions of the gun train and elevation mechanism supported on the pedestal 12 can rotate with the gun in azimuth and can elevate and depress the gun in any azimuth position.

A periscopic sight, sight S, is mounted on the carriage 13, so that the gunsight tubes and the eyepiece are fixed for all positions of the gun in both train and elevation. The periscopic sight S is an angle or elbow type sight. It includes a rearwardly projecting sighting tube 22 mounting an eyepiece 22a, and a vertical periscopic tube 24,

which is coaxially mounted within the tubular pedestal 12 of the gun mount. The lower end of the gunsight S is mounted on the carriage 13 by a bracket 25, the details of which are not critical to the invention. Thus, the gunsight S, although it may be raised and lowered in its entirety as the carriage 13 is raised and lowered by the screwjack 13a (FIG. 1), is constructed so that in action, the tubes 22 and 24 of the gunsight S are fixed, and unaffected by either training or elevation of the gun G, or by combinations of these motions.

General description of the gunsight The gunsight S is provided with a lower azimuth mirror A (FIGS. 1, 4, 7 and 11), which is fixed at the junction of the sighting tube 22 and the periscope tube 24, for directing light from the target through the sighting tube 22, and into the eyepiece 22a.

An upper azimuth mirror A1 (FIGS. 2, 7 and lO-l2) is also provided in the gunsight S. At zero train or azimuth, the upper azimuth mirror A1 is at 90 to the lower azimuth mirror A. However, the upper azimuth mirror A1 rotates independently of the periscope tube 24 about the axis (a)(a), FIGURES 7 and and follows the gun in 'its azimuth motion. The assembly for retaining the upper azimuth mirror Al on the fixed periscope tube 24 is indicated generally at 26, in the exploded perspective of FIGURE 10, and will be described in detail presently.

An elevation mirror E (FIGS. 2, 7, 8 and 10 to 12) is rotatably mounted on the upper azimuth mirror A1, by an assembly indicated generally at 28, in the exploded perspective of FIGURE 10. The elevation mirror E rotates about an axis (e1)-(e1) (FIGS. 7 and 10), which is parallel to the elevation axis (e)(e) of the gun (FIG. 7). The elevation mirror E is rotated by elevation and depression of the gun by means of a linkage assembly L (FIGS. 7, 8 and 10), which is constructed so that for any angle of elevation or depression of the gun, the elevation mirror E rotates through the same angle.

As mentioned above, the upper azimuth mirror A1 and the elevation mirror E are boresighted with the gun G, and turn with the gun and its trunnion assembly 14 in azimuth. The aforesaid rotation of the upper azimuth mirror A1 relative to the lower azimuth mirror A, as well as the elevation and depression of the elevation mirror E, is accomplished by a shaft (FIGS. 7 and 10) which extends through one of the gun trunnions 14. The shaft 30 elevates and depresses the elevation mirror E through the linkage L previously described. Since the elevation mirror E is rotatably connected to the upper azimuth mirror A1 by the mechanism 28 indicated generally at FIGURE 10 and previously mentioned, rotation of the gun in azimuth rotates both the elevation mirror E, and the upper azimuth mirror A1 in azimuth, by means of the trunnion mounted shaft 30.

If the optical system of the gunsight S contained nothing more than the two azimuth mirrors A and Al, the elevation mirror E, and the conventional lens system of a telescopic sight, motion of the gun in azimuth, with the attendant rotation of the upper azimuth mirror A1 relative to the lower azimuth mirror A, would cause the image of the target as seen through the eyepiece 22a of the sight to revolve. Similarly, rotation of the elevation mirror E, as it follows elevation and depression of the gun, would cause the image of the target as seen in the eyepiece E to revolve. In accordance with the present invention optico-mechanical means are provided for cancelling out this normally inherent rotation of the image during train and elevation of the gun, and this correction is made completely automatically, without requiring any adjustments, knobs, controls or the like for operation by the gunner.

This automatic cancelling out of the inherent image rotation of the gunsight is provided by mounting a derotating prism D in the periscope tube 24, between the 4- upper and lower azimuth mirrors (FIGS. 10 and 11). The prism D is mounted in a sleeve, or cage, 32 (FIG. 10), which is rotatably mounted on the upper end of the fixed periscope tube 24 of the gunsight. The prism sleeve 32 is rotated at half speed by reduction gearing indicated generally at 34.

Half speed rotation of the sleeve 32 and the prism D occurs when the upper azimuth mirror A1 is rotated. This motion is provided through the azimuth mirror mounting, indicated generally at 26 (FIG. 10), and the gear reduction 34 just mentioned.

Half speed rotation of the sleeve 32 and its prism D, when the gun is moved in elevation, is provided by mechanism indicated generally at 36 (FIG. 10), through the azimuth mirror mounting, indicated generally at 26 in FIGURE 10. The gunsight elevation mechanism causes half speed rotation of the sleeve 32 and the prism D, while preventing rotation of the upper azimuth mirror A1. The half speed gear reduction mechanism 34 for the prism D is thus independently operated by either train or elevation of the gun, and neither of these motions of the upper azimuth and elevation mirrors have any effect on the gunsight tubes 22 and 24.

Having completed a general description of the gun and gunsight assembly of the present invention, a detailed description of the various elements previously described will now .be presented.

Gun train mechanism As previously mentioned, in the embodiment of the invention illustrated and described, the gunner operates the gun train mechanism 19, for training the gun in azimuth, by means of a combined azimuth handle and trigger 19a (FIGS. 1 and 4). Referring to FIGURE 4, the azimuth handle 19a is a crank connected to a vertical shaft 40 mounted in the gun carriage 13. The shaft 40 is keyed to a small sprocket 41 that drives a chain 42, trained around a large sprocket 43. A small sprocket 44 is connected to the large sprocket 43, and both sprockets are rotatably mounted on a vertical countershaft 45. The small sprocket 44 drives a chain 46, which is trained around a large sprocket 47, secured to the lower end of the tubular rotatable trunnion mounting sleeve 16, previously described. The gun trunnions 14 are secured to a plate 56 mounted on the upper end of the sleeve 16. Thus, rotation of the crank 19a by the gunner, trains the gun in azimuth, and this is accomplished without affecting the elevation of the gun, as will be seen presently.

Gun elevation mechanism As previously mentioned, in the embodiment of the present invention, the gun is independently elevated by the gunners elevation crank 18a (FIG. 1). The elevation mechanism, indicated generally at 26, is constructed so that elevation and depression of the gun is accomplished without disturbing the fixed portions 22, 22a and 24 of the gunsight, which are mounted on the carriage 13. Referring to FIGURES 4 to 6 and to the diagram of FIGURE 9, the gun elevation mechanism converts rotation of the gun elevation crank 18a into a vertical reciprocation of a rack (FIG. 4), which drives a sector gear 52. keyed to stub shaft 54, which shaft is rotatably mounted in the left hand gun trunnion (broken away in FIG. 4). The rack 50 is backed up by a roller and mounting bracket assembly secured to a plate 56 carried on the upper end of the trunnion assembly mounting sleeve 16. A sector gear 58 is keyed to the elevation shaft stub 54, and meshes with a sector gear 60 secured to the cradle 61 of the gun.

The mechanism for raising and lowering the elevation rack 54 in the embodiment of the invention being illustrated and described, is special from an internal epicyclic gear train, known as a harmonic drive. This drive, indicated generally at H, converts rotary motion of the elevation crank to straight line motion. Referring to FIG- URE 4, the gun elevation crank 18a is connected to a cross shaft 62 that drives a small pinion 64. A chain 66 is trained around the small pinion 64 and around another small pinion 68, the latter pinion being secured to a laterally extending worm shaft 70, rotatably mounted in the gun carriage 13.

As seen in FIGURES 5, 6 and 9, the worm shaft 70 drives a worm 72, which is meshed with a worm wheel sector 74. The web 74a of the worm wheel sector 74, is secured to the flanged head 75, of a stub shaft 76. The shaft 76 is rotatably mounted in the gun carriage 13. The shaft 76 is shouldered at 77 (FIG. 5), and is retained in a wall of the carriage 13 by a nut 78, clearance being provided to permit rotation of the shaft. The flange on the shaft 76 that mounts the web 74a of worm wheel sector 74, carries an offset pin 80, forming a planet gear shaft which is otfset from the axis of the worm wheel shaft 76. When the worm wheel 74 is rotated by the worm 72, the pin 80 acts as a crank. Rotatably mounted on the offset pin 80, is a planet gear 82, which is meshed with an internal sun gear sector 84, secured to the gun carriage 13.

The pitch diameter of the planet gear 82 is exactly half the pitch diameter of the internal sector sun gear 84. A crank arm 86 is secured to the face of the planet gear 82, and is apertured at 87 (x) to receive a pin 88 (FIGS. 4 and 9), that projects from a lower cutaway portion 90, of an internal gun elevating tube 92. As seen in FIG- URE 6, the axis (x) of the pin 88 -is exactly on the pitch diameter of the planet gear 82. This is a special case of an epicyclic gear train, namely, a case wherein the planet gear pitch diameter is exactly half the pitch diameter of the sun gear, with the planet gear being rotated about its own center. This provides the harmonic drive H previously mentioned, so that the point (x) of the planet gear 82 will move in a straight vertical line (y)-(y), as indicated in FIGURES 6 and 9. Advantage is taken of this straight line action of the harmonic drive epicyclic gear assembly, by connecting the pin 88 to the lower end 90 of the internal gun elevating tube 92 that surrounds the periscope tube 24 of the gun sight S, as described previously.

In order to permit the gun mount sleeve 16 to rotate without affecting the raising and lowering of the gun elevating tube 92, an intermediate gun elevating sleeve 94 is rotatably supported on the non-rotatable gun elevation tube 92 by upper and lower bearings. The intermediate sleeve 94 is slidably mounted within the trunnion assembly mounting sleeve 16. Extending across the top of the rotatable, slidable gun elevating sleeve 94 is a plate 96, from which the gun elevation rack 50 previously referred to projects.

The gun elevation rack 50 is slidably mounted through a squared slot formed in the upper plate 56 of the trunnion assembly mounting sleeve 16. Hence the gun elevation rack 50 and its rotatably mounted intermediate sleeve 94- can rotate with the gun in azimuth, while the gun elevating tube 92 remains fixed against rotation by the pin 88 of the harmonic drive 61. However, the gun elevating tube 92, when raised and lowered by the harmonic drive, raises and lowers the intermediate gun elevation sleeve 94, along with the rack 50, and hence elevates or depresses the gun at any position of the gun in azimuth.

Thus through this harmonic drive mechanism, the gun is elevated or depressed by operation of the elevation crank 18a, and motion of the gun in azimuth has no effect on the elevation drive.

The optical system The optical system, the major elements of which have been briefly described, will now be explained in detail. As mentioned, in the present invention the optical system includes a periscopic gunsight, which has a vertically disposed periscope tube 24 centered on the azimuth axis (a)-(a) of the gun. Tube 24, being mounted on bracket 25 connected to the gun mount carriage 13, is normally stationary, and neither elevates nor trains with the gun. The only time that the gun sight S, including the periscope tube 24 and the sighting tube 22, move, is when the entire gun and gun mount is raised and lowered as shown in FIGURE 3.

As previously mentioned, it is a feature of the present invention that although the gun sight is a periscopic sight, having a fixed periscope tube 24 within the pedestal 12 that supports the gun mount M, neither train of the gun in azimuth, nor elevation or depression of the gun, affect the image of the target received at the eyepiece 22a at the end of the rearwardly projecting sighting tube 22 This cancelling out of the rotation of the image, which would normally occur with both train and elevation of the gun, if a conventional periscopic sight were employed, is effected by an optico-mechanical system including the derotating prism D and its mounting sleeve 32, previously described in general.

Details of the moving parts of the gun sight are best seen in the exploded perspective of FIGURE 10. These parts are shown in their normal relation in FIGURE 7. The construction of this portion of the gun sight is as follows: The de-rotating prism sleeve or cage 32 is rotatably mounted on and supported by an upper end ring 100 (FIGURE 10) of the periscope tube 24. Suitable bearings and securing means are provided for the sleeve 32, the details of which are not critical to the present invention, representing mere conventional machine design.

In order to provide the gunner with an image that is not rotated due to motion of the gun in either azimuth or elevation, the half speed drive 34 for the prism cage or sleeve 32 previously referred to, is provided. The half speed drive 34 operates as follows: A ring gear 102 is mounted on the upper end of the prism cage 32. The ring gear 102 meshes with a small lower pinion 104, which is integral with an upper pinion 106, the pitch diameter of which is twice that of the lower pinion 104. The dual pinion unit 104, 106 is rotatably mounted on a vertical pin 107, secured in a socket 107a formed in a vertical extension of the upper portion of the periscope tube 24.

The larger pinion 106 of the dual pinion assembly 104, 106 meshes with an upper ring gear 108, which has a pitch diameter smaller than that of the ring gear 102 mounted on the prism cage 32. The cage for the upper azimuth mirror A1 has a depending sleeve portion 110 that is rotatably mounted in the upper ring gear 108, which has a bore 112 for rotatably receiving the sleeve 110. The azimuth mirror A1 is retained in position by the assembly 26 previously referred to in the general description of the sight. The retaining assembly 26 includes a flange 114 projecting from one side of the upper ring gear 108. An upper mounting bracket 116, carries a flange 118, that is screwed to the flange 114 of the upper ring gear 108 by screws 120. The bracket 116 is rotatably connected to the cage of the upper azimuth mirror A1, by means of a shouldered bolt 121. The bolt 121 passes through an aperture 121a in the upper bracket 116, through a central aperture 121k formed in a bevel gear 122, the gear 122 having its center on the vertical axis (a)(a) of the periscope tube 24. The shouldered bolt 121 is threaded into a boss 121a formed on the upper azimuth mirror cage. The bevel gear 122 is pinned to the upper bracket 116 by a pin 123, pressed into a hole 123a in the bevel gear. With this construction, rotation of the bracket 116 turns the upper ring gear 108, the upper idler pinion 106, and the smaller idler pinion 104. This rotates the lower ring gear 102 on the prism cage 32, and hence turns the de-rotating prism D. The pitch diameters of the ring gears 102, 108, and of the idler pinions 104, 106, are selected so that the prism D rotates at half the speed of rotation of the upper bracket 116.

.As will be seen, the bracket 116 is rotated when the gun is turned in azimuth, and in elevation, and this rotation of the bracket 116 cancels out rotation of the image at the eyepiece of the gunsight, which would occur if the de-rotating D prism and its half speed drive 34 were not provided.

The elevation mirror E is rotatably mounted on the cage for the upper azimuth mirror A1 by means of a bevel ring gear 124. The ring gear 124 is rotatably secured to the cage of the upper azimuth mirror All by means not shown, and not critical to the invention. The elevation mirror E is pinned to the ring gear 124 by dowel pins 126. The cage of the elevation mirror E is apertured at 128, so that light beams from the target T are reflected by the elevation mirror and directed along the axis (e1)(e1) to the reflecting surface of the upper azimuth mirror A1.

The upper bracket 116 is rotated about the axis (a)--(a) when the gun is rotated in azimuth, by the mechanism 19, in order to cancel out an efl'ect which would otherwise result in rotation of the image of the target, as seen in the eyepiece 22a. Rotation of the gun in azimuth is effected by turning the trunnion 14 about the vertical axis (a)(a) (FIGURE 10). The elevation mirror shaft is carried around the vertical axis (a)-(a) by the trunnion 14 through which the shaft extends. The shaft 30, being connected to the elevation mirror E, causes the mirror E to bodily turn around the same axis.

The structure 28 which mounts the elevation mirror on the upper azimuth mirror connects the two mirrors together for simultaneous motion in azimuth. When this occurs, the meshed connection between the elevation bevel gear 124 and the bevel gear 122 rotates the bevel gear 122 about its axis (a)(a). Since the bevel gear 12.2 is connected to the upper bracket 116 by the screw 121 and the pin 123, the bevel gear is functionally integral with the bracket 116. Thus the rotation of the gun in azimuth turns both the upper mirror A1, and the bracket 116. As just described, rotation of the bracket 116 turns the de-rotating prism D, at half speed, which maintains the target image erect at the eyepiece 22a.

As mentioned, the upper bracket 116 is also rotated about the axis (a)(a) when the gun is turned in elevation, in order to cancel out an effect which would also other-wise cause rotation of the image of the target, as seen in the eyepiece 22a.

When the gun is rotated in elevation, and is stationary in azimuth, the trunnion 14 through which the shaft 30 extends is stationary. This prevents the elevation mirror E, and the upper azimuth mirror A1 which mounts the elevation mirror, from bodily rotating about the vertical axis (a)-(a).

However, motion of the gun in elevation causes the linkage L to turn shaft 3% in the trunnion 14 through which the shaft extends, and hence rotates the elevation mirror E about its horizontal axis (c)(e), FIG. 16. This rotation of the elevation mirror E, turns the bevel ring gear 124 rotatably mounted on the cage of the upper azimuth mirror All, but has no effect on the position of the upper azimuth mirror. The bevel ring gear 124 rotates the bevel gear 122 about the vertical axis (a)(a), and the bevel gear 12-2 rotates the upper bracket 116 by means of the pin 123. When the bracket 116 rotates, so does the upper ring gear 1%, which drives the prism D at half of the gun elevation speed, thereby insuring that the image of the target at the eyepiece remains erect during gun elevation. The shouldered screw 12-1 accommodates this rotation of the upper bracket 116 without exerting a rotating force on the upper azimuth mirror.

As mentioned in the opening statements of this specification, the automatic cancelling of the tendency of the image to rotate in a fixed periscopic sight of this type is accomplished by connections made to the gun, there being no knobs, adjustments or other means requiring the operators attention. The shaft 30, which mounts the elevation mirror E in the gun trunnion 14, not only serves to rotate the elevation mirror E about its elevation axis (e1)(e1), but also causes the elevation mirror E and the azimuth mirror A1 connected thereto, to rotate in unison when the gun trains in azimuth. In either case, the de-rotation prism D is turned at half speed, and cancels out any rotation of the image that would otherwise occur.

As previously mentioned, the elevation mirror E is rotated about its axis (e1)-(e1) by a linkage L connected to the gun elevation pintle 18. This linkage, best seen in FIGURES 7 and 8, comprises a crank secured at one end to the gun elevation pintle 18, and the other end of the crank 140 is pinned to a link 142, which in turn is pinned to the outer end of a lower crank 144. The inner end of the lower crank 144 is connected to the shaft 34 that projects from elevation mirror E (FIG. 10), and extends through a trunnion 14. The geometry of the linkage assembly L is such that rotation of the elevation mirror follows exactly the angle of elevation or depression of the gun about the pintles 18.

FIGURE 11 is a diagram showing the relation of the critical parts of the optical system. In this diagram, the gun (not shown) is assumed to be at zero train and elevation. Light beams from the target impinging on the elevation mirror E are indicated by a vertical arrow T. These beams are reflected by the elevation mirror, as indicated by a vertical arrow T1, and directed to the upper, rotatable azimuth mirror A1. The light beams are reflected down from A1 (along axis (a)(a), FIG 10), as indicated by a horizontal arrow T2, which is in the plane of the paper and points to the left. These beams pass through the de-rotating prism D, and emerge as indicated by an arrow T3. The arrow T3 has been turned through an angle of 90 by the prism, and so points toward the viewer of FIGURE 11 (in a plane perpendicular to the paper). The light beams pass through an objective lens 150, which inverts the beams and forms a real image indicated by an arrow T4, in a field lens 152. The image represented by the arrow T4, is still perpendicular to the paper, but it now points away from the viewer of FIGURE 11. The image T4 is reflected by the lower, fixed azimuth mirror A, and is directed to a relay, or erecting lens 154 as indicated by a downwardly pointed arrow T5. In FIG- URE 11, the lens 154 and the eyepiece have been rotated 90 to place them in the plane of the paper, for purposes of illustration. The inverted reflected image T5 is erected by the relay lens 154, and is directed to the eyepiece 22a as indicated by a vertical, upwardly pointing arrow To. The beams indicated by arrow T6 enters the eyepiece 22a which forms a virtual, erect and enlarged image T7 of the target, for viewing by the gunner.

FIGURE 11A is a side view of a dove prism showing how it crosses incident light beams p and q in the plane of the paper, which is the mid-plane of the prism. If the prism D of FIGURE 11A were turned 45 degrees rem the position shown, the beams p and q would be turned 90 and would lie in a plane perpendicular to the paper.

The simplified plan diagram of FIGURE 12 shows the position of the de-rotating prism D, when the gun is at zero train in azimuth and is at zero elevation. Under these conditions the mid-plane (d)(d) of the dove prism D is at an angle of 45 light T from the target, with the lateral reflected beam T1. The prism is also at an angle of 45 with the bore of the gun G, and is at an angle of 90 to the plane of elevation mirror E.

Operation The operation of the mechanism 13a, etc., for raising and lowering the entire gun mount from the position of FIGURE 1 to that of FIGURE 3 (with the gun mount elevated at 90), have been referred to briefly, but is not critical to the invention, and hence will not be redescribed.

Furthermore, the azimuth drive is straight forward, and the harmonic elevation drive and its operation have been described in detail, and it is believed that their operation is clear.

As described previously, the gun can be trained in azimuth without affecting gun elevation, and the gun can be elevated and depressed without affecting gun azimuth.

Also, no gun motion in train or elevation is transmitted to the gunsight tubes 22 and 24, mounted on the carriage 13 Referring to FIGURE 4, the independent azimuth motion of the gun is made possible by the provision of the intermediate sleeve 94, carrying the elevation rack 50. Although the sleeve 94 mounts the gun elevation rack 50 which moves in azimuth with the gun, the sleeve 94 is rotatably supported by the non-rotatable gun elevation tube 92, and hence gun train does not disturb the elevation mechanism, including the carriage mounted harmonic drive elements 70-88 (FIGS. 5, 6 and 9).

As a corollary, the construction just described, while permitting motion of the gun in azimuth without disturbing the gun elevation mechanism; also permits motion of the gun in elevation without disturbing the gun train mechanism. As seen in FIGURE 4, although the intermediate sleeve 94 rotates with the gun in azimuth, it is slidably mounted in the sleeve 16 that supports the gun mount. Thus, the elevation tube 92 can support the intermediate sleeve 94, by means of the non-rotatable pin 88 of the harmonic drive H. Thus the harmonic drive can elevate and depress the gun by moving the intermediate sleeve 94 up and down relative to the rotatable gun mount supporting sleeve 16.

As to the optical system of the gunsight S, when the gunner trains the gun in azimuth by means of his azimuth crank 19a (FIG. 4), the gun trunnion support sleeve 16, and the gun trunnions 14, rotate relative to the pedestal 12. Since the lateral shaft 30 connected to the elevation mirror E passes through one of the gun trunnions (FIGS. 7 and rotation of the gun in azimuth rotates the elevation mirror E with the gun, about the vertical azimuth axis (a)-(a). Since the elevation mirror E is mounted on the cage for the upper azimuth mirror A1, rotation of the gun in azimuth causes a corresponding rotation of the upper azimuth mirror A1 about the vertical axis (a)(a) of the gunsight, so that the sight follows the target in azimuth.

This rotation of the gun in azimuth, turns the upper bracket 116 and the bracket 114 bolted thereto. This rotates the upper ring gear 108, which meshes with the larger idler pinion 106, which in turn causes the smaller idler pinion 104 to rotate the lower ring gear 102, attached to the upper portion of the de-rotating prism cage 32.

The prism D is thus rotated through an angle which is exactly half of the angle of the gun azimuth motion. With the prism D mounted in the 45 position of FIG- URE 12, when the gun is at zero train and elevation, the resulting half speed rotation of the prism D cancels out the inherent rotation of the image of the target, which would otherwise occur.

When the gun is elevated or depressed, the linkage L (FIGS. 7 and 8) connected to a gun pintle 18 at one end, and to the lateral shaft 30 at the other end, rotates the gun elevation mirror E with the gun. The elevation mirror E is rotatably mounted on the cage of the upper azimuth mirror A1 by the bevel gear 124 (FIG. 10), pinned to the elevation mirror.

The resulting rotation of the elevation mirror bevel gear 124, turns the bevel gear 122 which is pinned to the upper bracket 116 (FIGS. 7 and 10). Thus the upper bracket 116 drives the prism D at half speed, just as it does when the gun is trained in azimuth. Since trunnion 14, through which the lateral elevation mirror shaft 30 passes, does not turn during gun elevation, the elevation mirror, shaft 30, and the trunnion 14 prevent rotation of the upper azimuth mirror when the gun is stationary in azimuth. The shouldered screw 121 permits the upper cage 116 and the bevel gear 122 pinned thereto to rotate about the vertical axis (a)(a) during gun elevation, Without exerting a turning force on the upper azimuth mirror. The upper cage 116 can turn the upper ring gear 108 of the half speed drive for the prism D, while the upper azimuth mirror remains stationary, because of the rotatable connection between the depending sleeve 110 of the upper azimuth mirror cage, and the upper ring gear 1418 of the half speed prism drive 34.

Although a clove prism is the preferred optical derotating means, in the broader aspects of the invention, other optics could be employed. For example, a K-prism (a double reflection and plane mirror assembly), or a phecon prism could be substituted for the de-rotating dove prism D.

Having completed a detailed description of the invention so that those skilled in the art may practice the same, I claim:

1. A gun and gunsight assembly comprising assembly support structure, a gun mount including trunnion means mounted on said support structure for motion in azimuth, a gun mounted in said trunnion means for motion in elevation, a periscopic gunsight having a periscope tube fixedly mounted on said support structure and disposed on the gun azimuth axis, an upper azimuth mirror rotatable on said periscope tube, fixed sighting tube means connected to the lower end of said fixed periscope tube, an elevation mirror to one side of said upper azimuth mirror, means mounting said elevation mirror for rotation about an axis parallel to that of said gun trunnion means, said elevation mirror being at 45 to its axis of rotation, said elevation and upper azimuth mirrors being disposed between and below said gun trunnion means; means connected to the gun for rotating said elevation and upper azimuth mirrors together about the axis of said periscope tube to follow gun motion in azimuth and for rotating said elevation mirror independently of the upper azimuth mirror but through the same angle as that of gun motion in elevation; optical target image de-rotating means rotatably mounted in said periscope tube, and means connected to said gun for rotating said optical target image de-rotating means whenever the gun is moved in either azimuth or elevation for maintaining the target image erect for all gun positions although said sighting tube means remains stationary.

2. The assembly of claim 1, wherein said optical target image tie-rotating means is a prism mounted in said periscope tube, and said means connected to the gun for rotating the prism turns the prism through one half of the angular motion of the gun in either azimuth or elevation.

3. A gun and gunsight assembly comprising a hollow vertical pedestal, a gun mount comprising a gun mounting sleeve rotatably mounted in said pedestal, gun trunnions mounted on the upper end of said sleeve, a gun mounted on said trunnions for motion in elevation, an intermediate gun elevation sleeve slidable in said gun mounting sleeve, a gun elevation tube rotatably supporting said intermediate gun elevation sleeve, a periscopic gunsight having a fixed periscope tube mounted inside of said gun elevation tube, rotatable azimuth and elevation mirrors mounted on the upper end of said periscopic tube and disposed below the gun and between said trunnions, means connected to a gun trunnion for moving said azimuth and elevation mirrors in azimuth, and means connected to the gun and to said elevation mirror for moving the elevation mirror in elevation along with elevation motion of the gun.

4. The assembly of claim 3, wherein a target image de-rotating prism is rotatably mounted in said periscope tube, and means connecting gun and gun mount, and to said prism, for turning the prism about a vertical axis through one half of the angular motion of the gun in both azimuth and elevation.

5. The assembly of claim 3, wherein said elevation mirror is rotatably mounted on said azimuth mirror.

6. The assembly of claim 5, including a target image de-rotating prism rotatably mounted in said periseope tube, means for rotating said prism, and a bevel gea-r assembly connected between said elevation mirror and said prism rotating means.

7. The assembly of claim 6, wherein said prism rotating means is a gear reduction assembly that rotates the prism through half of the angle of gun elevation.

8. A gun and gunsight assembly, said assembly comprising a gun mount, gun mount supporting means comprising a hollow pedestal, a gun trunnion assembly, means for mounting said gun trunnion assembly on said pedestal for rotation in azimuth, gun pintle means for mounting said gun on said trunnion assembly for gun motion in elevation, means for training said trunnion assembly and the gun in azimuth, means for elevating and depressing said gun; a' periscopic gunsight, said gunsight having a sighting tube, and a periseope tube, said periseope tube projecting upwardly from said sighting tube, means for mounting said gunsight in a fixed position on said gun mount with said periseope tube being disposed within, and coaxial with said hollow pedestal; said gunsight having a lower azimuth mirror fixed at the junction of said sighting and periscope tubes, an upper azimuth mirror at the upper end of said periseope tube, means for mounting said upper azimuth mirror on said periseope tube for rotation about the tube axis, the plane of said upper azimuth mirror being at an angle of 45 degrees to the periseope tube axis and at 45 degrees to :an axis parallel to the gun elevation axis, an elevation mirror, means mounting said elevation mirror on said upper azimuth mirror for rotation about an axis that is parallel to the gun elevation axis, means connected to said gun mount for rotating said upper azimuth mirror about the axis of said periscope tube through the angle of azimuth motion of the gun, means connected to the gun for turning said elevation mirror about its axis to follow the elevation and depression of said gun about its elevation axis, target image de-rotating prism means rotatable in said periseope tube between said lower and upper azimuth mirrors, means for rotating said prism means about the axis of the periseope tube for cancelling out the optical effect of rotating said upper azimuth mirror relative to said lower azimuth mirror as the upper azimuth mirror trains in azimuth with the gun, and means connected between said elevation mirror and said prism means for rotating said prism means about the periseope tube axis where the gun moves in elevation for cancelling out the optical efiect of rotating said elevation mirror in elevation relative to said azimuth mirrors.

9. The assembly of claim 8, wherein said target image de-rotating prism means is a dove prism, said dove prism being at an angle of 45 to axis of said sighting tube of the gunsight, and at an angle of 90 to the plane of said elevation mirror, when the gun is at zero azimuth :and elevation, said prism rotating means causing the prism to rotate at half the speed of gun motion in both azimuth and elevation.

10. A gun and gunsight assembly, said assembly com prising a gun mount, gun mount supporting means comprising a hollow pedestal, said gun mount having laterally spaced gun trunnion members, means mounting said trunnion members on said pedestal for rotation in azimuth, gun pintle means for mounting said gun on said trunnion members for gun motion in elevation, means for training said trunnions and the gun in azimuth, means for elevating and depressing said gun in the trunnions; a periscopic gunsight, said gunsight having a sighting tube, and a periscope tube, said periseope tube projecting upwardly m 58 4.1 g g e, means for mounting said gunsight in a fixed position on said gun mount with said periseope tube being disposed Within, and coaxial with said hollow pedestal, said gunsight having a lower azimuth mirror fixed at the junction of said sighting and periseope tubes, an upper azimuth mirror rotatable on said periseope tube, said upper azimuth mirror being at an angle of to the lower azimuth mirror at zero gun train and elevation, the plane of said upper azimuth mirror being at an angle of 45 to the periseope tube axis and at an angle of 45 to an axis parallel to the gun elevation axis, an elevation mirror, means mounting said elevation mirror on said upper azimuth mirror for rotation about an axis parallel to the gun elevation axis, said latter mirrors being disposed between said trunnions and below the gun, means connected to the gun mount for rotating said upper azimuth mirror about the axis of said periscope tube when the gun mount moves in azimuth, means connected to the gun for turning said elevation mirror about its axis to follow the elevation and depression of the gun, a target image de-rotating prism rotatably mounted in said periscope tube between said lower and upper azimuth mirrors, means for rotating said prism about the axis of the periscope tube at half of the azimuth speed of the gun, for cancelling out the optical efiect of rotating said upper azimuth mirror'relative to said lower azimuth mirror as the upper azimuth mirror trains in azimuth with the gun, and means connected between said elevation mirror and said prism for rotating said prism about the periseope tube axis at half of the elevation speed of the gun, for also cancelling out the optical efiect of rotating said elevation mirror relative to said upper azimuth mirror.

11. The assembly of claim 10, wherein said means connecting the elevation mirror to the gun is a shaft which extends through one of said gun trunnion members and is connected at one end to said elevation mirror, and link means connected to the other end of said shaft and to said gun for rotating said elevation mirror in accordance with gun elevation.

12. The assembly of claim 10, wherein said elevation mirror drives said prism through a bevel gear fixed to the elevation mirror, meshed with a bevel gear rotatably mounted on said upper azimuth mirror.

13. A gun, gun mount and gunsight assembly, means for supporting said assembly comprising a hollow vertical pedestal, said gun mount comprising centrally apertured gun mounting means rotatably supported on said pedestal, gun trunnions mounted on said gun mounting means; a gun mounted on said trunnions for motion in elevation; said gun mount also comprising gun elevation means, said gun elevation means comprising an intermediate, centrally apertured gun elevation member, means mounting said gun elevation member in said pedestal for vertical and rotating motion relative the pedestal, a non-rotatable gun elevation tube within said pedestal for rotatably supporting said intermediate gun elevation member, means for raising and lowering said tube, said gunsight comprising a periseope tube mounted inside of said gun elevation tube, rotatable azimuth and elevation mirror means mounted on the upper end of said periscopic tube, means connecting said mirror means to the gun mount for moving said mirror means in azimuth when the gun and gun mount move in azimuth, and means connecting said mirror means to the gun for moving said mirror means in elevation when the gun moves in elevation.

14. A gun and gunsight assembly comprising support structure including a hollow pedestal, gun trunnion means, a gun mounted on said trunnion means for elevation and depress-ion, sleeve means for rotatably mounting said trunnion means on said pedestal, an intermediate sleeve axially slidable within said sleeve means, a rack projecting from said intermediate sleeve and disposed to one side of the sleeve axis, pinion means operable by said rack for moving the gun in elevation, a gun elevating tube within said intermediate sleeve and supporting the latter for rotation, means for raising and lowering said tube for elevating and depressing the gun; and a gunsight having 13 a non-rotata b1e periscope tube connected to said support structure and extending through said elevating tube to a terminal position within said trunnion means.

15. A gun and gun mount assembly, and a periscopic gunsight, said gun mount assembly comprising a hollow pedestal, a pair of spaced gun trunnions, trunnion support means rotatably mounted on said pedestal, a gun mounted on said trunnions for motion in elevation, means for moving said trunnion support means and the gun in azimuth, axially slidable sleeve means within said trunnion support means for moving said gun in elevation, said gunsight having fixed periscope tube means mounted coaxially Within said axially slidable sleeve means, said gunsight having rotatably mounted azimuth and elevation mirror means mounted on the upper end of said fixed periscope tube and disposed between said trunnions, and means connecting said mirror means to said assembly for rotating both mirror means in azimuth and the elevation mirror means alone in elevation in accordance with motion of the gun in azimuth and in elevation. mesnfictivelv References Cited by the Examiner UNITED STATES PATENTS 1,188,844 6/1916 Shurmann.

1,371,891 3/1921 Haller 8941 X 2,152,726 4/1939 Baroni 8872 2,184,615 12/1939 Gunther 8941 X 14 2,366,410 1/1945 Klemperer et a1 89-375 2,385,348 9/1945 Chafee 8941 X 2,414,608 1/ 1947 Pontius 8937.5 2,546,111 3/1951 Rattray 8070 2,569,010 9/1951 Kuzmitz et a1. 33-49 3,204,523 9/1965 Daily 881 FOREIGN PATENTS 829,165 6/1938 France. 448,250 12/ 1934 Great Britain.

References Cited by the Applicant UNITED STATES PATENTS BENJAMIN A. BORCHELT, Primary Examiner.

S. C. BENTLEY, Assistant Examiner. 

15. A GUN AND GUN MOUNT ASSEMBLY, AND A PERISCOPIC GUNSIGHT, SAID GUN MOUNT ASSEMBLY COMPRISING A HOLLOW PEDESTAL, A PAIR OF SPACED GUN TRUNNIONS, TRUNNION SUPPORT MEANS ROTATABLY MOUNTED ON SAID PEDESTAL, A GUN MOUNTED ON SAID TRUNNIONS FOR MOTION IN ELEVATION, MEANS FOR MOVING SAID TRUNNION SUPPORT MEANS AND THE GUN IN AZIMUTH, AXIALLY SLIDABLE SLEEVE MEANS WITHIN SAID TRUNNION SUPPORT MEANS FOR MOVING SAID GUN IN ELEVATION, SAID GUNSIGHT HAVING FIXED PERISCOPE TUBE MEANS MOUNTED COAXIALLY WITHIN SAID AXIALLY SLIDABLE SLEEVE MEANS, SAID GUNSIGHT HAVING ROTATABLY MOUNTED AZIMUTH AND ELEVATION MIRROR MEANS MOUNTED ON THE UPPER END OF SAID FIXED PERISCOPE TUBE AND DISPOSED BETWEEN SAID TRUNNIONS, AND MEANS CONNECTING SAID MIRROR MEANS TO SAID ASSEMBLY FOR ROTATING BOTH MIRROR MEANS IN AZIMUTH AND THE ELEVATION MIRROR MEANS ALONE IN ELEVATION IN ACCORDANCE WITH MOTION OF THE GUN IN AZIMUTH AND IN ELEVATION, RESPECTIVELY. 